<customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui" onLoad="OnLoad">
  <ribbon>
    <tabs>
      <tab idMso="TabInsert">
        <group id="GroupInsertFlickr" label="Web" insertBeforeMso="GroupInsertIllustrations">
          <button id="flickrButton"
                  size="large"
                  label="Flickr Image" 
                  screentip="Insert an image from the Flickr(tm) service." 
                  onAction="OnFlickrInsert" 
                  getImage="GetImage" insertBeforeMso="PictureInsertFromFile" />
        </group>
      </tab>
    </tabs>
  </ribbon>
</customUI>